Diagnosis Of Susac Syndrome Research Articles

Optical Coherence Tomographic Findings in Susac Syndrome

Purpose: To report optical coherence tomographic (OCT) findings in Susac syndrome. Methods: A 15-year-old girl who had symptoms of deafness and encephalopathy was referred with a provisional diagnosis of Susac syndrome. Funduscopy revealed cotton wool spots and ischaemic cloudy swelling of the retina. Results: OCT taken from the abnormal retinal area showed increased reflectivity of the inner retinal layers and decreased reflectivity from the outer retinal layers and the retinal pigment epithelium due to shadowing. Neither intraretinal nor subretinal fluid were observed on the OCT imaging. OCT findings were compatible with the accepted view that the retinal pathology in Susac syndrome is due to arteriolar occlusion. Conclusion: OCT may be used as a complementary diagnostic method to fluorescein angiography in Susac syndrome.

DIFFUSION TENSOR IMAGING DEMONSTRATES FIBER IMPAIRMENT IN SUSAC SYNDROME

Susac syndrome is a rare disease, characterized by the triad of hearing loss, branch retinal artery occlusions, and encephalopathy with predominantly cognitive and psychiatric symptoms.1,2 Focal ischemic lesions in the corpus callosum detectable by conventional MRI are a typical feature of Susac syndrome.3,4 The lesions detectable by conventional MRI do not, however, explain the type and severity of the neuropsychological deficits.5,6 In this study, we tested the hypothesis of whether widespread tissue damage of the otherwise normal-appearing white matter (NAWM) could be detected in patients with Susac syndrome using diffusion tensor imaging (DTI).7 DTI is a noninvasive technique for detection of macro- and microstructural impairment of fiber integrity on the basis of normal values for the fractional anisotropy (FA).8 We hypothesized that the neuropsychological symptoms in patients with Susac syndrome correlated well with the FA aberrations detected with DTI. ### Methods. We investigated four patients with clinically diagnosed Susac syndrome. Their encephalopathic symptoms varied from mild cognitive impairment to severe acute psychosis. The symptoms were dyscalculia, impaired memory, hallucinations, paranoia, disorientation, emotional indifference, and strongly reduced alertness, motivation, concentration and cognitive flexibility. Diagnosis of Susac syndrome was established by the documentation of branch retinal artery occlusions, sensorineural hearing loss, encephalopathy, and the characteristic multifocal snowball-like hyperintense lesions on T2-weighted images (figure 1). In all patients, the diagnosis was based on the typical clinical triad, supported by the detection of the typical white matter (WM) lesions on T2-weighted MRI. Figure 1 T2-weighted images illustrating “snowball” lesions in the corpus callosum of Patients 1 through 4 (A) Patient 1 showed a lesion in the genu of the corpus callosum. (B) “Snowball” lesion in the splenium of the corpus callosum of Patient 2. (C) Patient 3 showed multiple lesions along the corpus callosum. (D) Lesion in the splenium of Patient …

Susac Syndrome with Frontal Intermittent Rhythmic Delta Activity (FIRDA)

Susac syndrome is a rare condition involving the brain, retina, and cochlea. Electroencephalogram (EEG) findings from published case reports show mainly generalized slowing. A 30-year-old man presented with acute onset of superior vision loss, unsteady gait, and hearing loss. This was accompanied by short-term memory loss and behavioral and mood changes. MRI showed multiple white matter hyperintensities. The EEG showed frontal intermittent rhythmic delta activity. A diagnosis of Susac syndrome was made and treatment with methylprednisolone, ASA, and Nimodipine was instituted. At one-year follow-up, bilateral hearing loss, mild visual impairment, and mood changes were still apparent. Frontal intermittent rhythmic delta activity can be seen in Susac syndrome.

MRI findings in Susac's syndrome.

Susac syndrome (SS) is a self-limited syndrome, presumably autoimmune, consisting of a clinical triad of encephalopathy, branch retinal artery occlusions, and hearing loss. All three elements of the triad may not be present or recognized, and MR imaging is often necessary to establish the diagnosis. To determine the spectrum of abnormalities on MRI in SS. The authors reviewed the MR images of 27 previously unreported patients with the clinical SS triad, and 51 patients from published articles in which the MR images were depicted or reported. All 27 patients had multifocal supratentorial white matter lesions including the corpus callosum. The deep gray nuclei (basal ganglia and thalamus) were involved in 19 (70%). Nineteen (70%) also had parenchymal enhancement and 9 (33%) had leptomeningeal enhancement. Of the 51 cases from the literature, at least 32 had callosal lesions. The authors could not determine the presence of callosal lesions in 18 of these patients, and only one was reported to have a normal MRI at the onset of encephalopathy. The MR scans in SS show a rather distinctive pattern of supratentorial white matter lesions that always involve the corpus callosum. There is often deep gray matter, posterior fossa involvement, and frequent parenchymal with occasional leptomeningeal enhancement. The central callosal lesions differ from those in demyelinating disease, and should support the diagnosis of SS in patients with at least two of the three features of the clinical triad.